From: Henrique Carvalho <henrique.carvalho@suse.com>
To: sfrench@samba.org
Cc: pc@manguebit.org, ronniesahlberg@gmail.com,
sprasad@microsoft.com, tom@talpey.com, bharathsm@microsoft.com,
ematsumiya@suse.de, linux-cifs@vger.kernel.org,
stable@vger.kernel.org
Subject: [PATCH 1/2] smb: client: serialize channel scaling path
Date: Mon, 13 Apr 2026 16:11:09 -0300 [thread overview]
Message-ID: <20260413191110.1508848-1-henrique.carvalho@suse.com> (raw)
Channel scaling serialization was coded at several call sites with plain
flag values in ses->flags, which duplicated the same bookkeeping in
reconnect and remount paths, and was missing in the mount path.
Move the CIFS_SES_FLAG_SCALE_CHANNELS acquisition and release inside
smb3_update_ses_channels(), and convert the session flags to bit indices
and their operations to bitops.
Make smb3_update_ses_channels return -EBUSY if there is already an
ongoing channel scaling operation.
Fixes: 556bb341f9f2e ("smb: client: introduce multichannel async work during mount")
Cc: stable@vger.kernel.org
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
---
fs/smb/client/cifsglob.h | 6 +++---
fs/smb/client/fs_context.c | 15 ---------------
fs/smb/client/smb2pdu.c | 24 ++++++++----------------
3 files changed, 11 insertions(+), 34 deletions(-)
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 709e96e07791..7b1323927711 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1049,8 +1049,8 @@ struct cifs_chan {
__u8 signkey[SMB3_SIGN_KEY_SIZE];
};
-#define CIFS_SES_FLAG_SCALE_CHANNELS (0x1)
-#define CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES (0x2)
+#define CIFS_SES_FLAG_SCALE_CHANNELS 0
+#define CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES 1
/*
* Session structure. One of these for each uid session with a particular host
@@ -1089,7 +1089,7 @@ struct cifs_ses {
bool domainAuto:1;
bool expired_pwd; /* track if access denied or expired pwd so can know if need to update */
int unicode;
- unsigned int flags;
+ unsigned long flags;
__u16 session_flags;
__u8 smb3signingkey[SMB3_SIGN_KEY_SIZE];
__u8 smb3encryptionkey[SMB3_ENC_DEC_KEY_SIZE];
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
index a46764c24710..e0e13c22e159 100644
--- a/fs/smb/client/fs_context.c
+++ b/fs/smb/client/fs_context.c
@@ -1166,27 +1166,12 @@ static int smb3_reconfigure(struct fs_context *fc)
/* Synchronize ses->chan_max with the new mount context */
smb3_sync_ses_chan_max(ses, ctx->max_channels);
- /* Now update the session's channels to match the new configuration */
- /* Prevent concurrent scaling operations */
- spin_lock(&ses->ses_lock);
- if (ses->flags & CIFS_SES_FLAG_SCALE_CHANNELS) {
- spin_unlock(&ses->ses_lock);
- mutex_unlock(&ses->session_mutex);
- return -EINVAL;
- }
- ses->flags |= CIFS_SES_FLAG_SCALE_CHANNELS;
- spin_unlock(&ses->ses_lock);
mutex_unlock(&ses->session_mutex);
rc = smb3_update_ses_channels(ses, ses->server,
false /* from_reconnect */,
false /* disable_mchan */);
-
- /* Clear scaling flag after operation */
- spin_lock(&ses->ses_lock);
- ses->flags &= ~CIFS_SES_FLAG_SCALE_CHANNELS;
- spin_unlock(&ses->ses_lock);
} else {
mutex_unlock(&ses->session_mutex);
}
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 5188218c25be..2eb13b2665a4 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -228,6 +228,10 @@ int smb3_update_ses_channels(struct cifs_ses *ses, struct TCP_Server_Info *serve
bool from_reconnect, bool disable_mchan)
{
int rc = 0;
+
+ if (test_and_set_bit(CIFS_SES_FLAG_SCALE_CHANNELS, &ses->flags))
+ return -EBUSY;
+
/*
* Manage session channels based on current count vs max:
* - If disable requested, skip or disable the channel
@@ -243,6 +247,7 @@ int smb3_update_ses_channels(struct cifs_ses *ses, struct TCP_Server_Info *serve
rc = cifs_chan_skip_or_disable(ses, server, from_reconnect, disable_mchan);
}
+ clear_bit(CIFS_SES_FLAG_SCALE_CHANNELS, &ses->flags);
return rc;
}
@@ -432,15 +437,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
goto out;
}
- spin_lock(&ses->ses_lock);
- if (ses->flags & CIFS_SES_FLAG_SCALE_CHANNELS) {
- spin_unlock(&ses->ses_lock);
- mutex_unlock(&ses->session_mutex);
- goto skip_add_channels;
- }
- ses->flags |= CIFS_SES_FLAG_SCALE_CHANNELS;
- spin_unlock(&ses->ses_lock);
-
if (!rc &&
(server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL) &&
server->ops->query_server_interfaces) {
@@ -450,11 +446,11 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
* is in progress. This will be used to avoid calling
* smb2_reconnect recursively.
*/
- ses->flags |= CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES;
+ set_bit(CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES, &ses->flags);
xid = get_xid();
rc = server->ops->query_server_interfaces(xid, tcon, false);
free_xid(xid);
- ses->flags &= ~CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES;
+ clear_bit(CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES, &ses->flags);
if (!tcon->ipc && !tcon->dummy)
queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
@@ -492,10 +488,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
}
skip_add_channels:
- spin_lock(&ses->ses_lock);
- ses->flags &= ~CIFS_SES_FLAG_SCALE_CHANNELS;
- spin_unlock(&ses->ses_lock);
-
if (smb2_command != SMB2_INTERNAL_CMD)
cifs_queue_server_reconn(server);
@@ -609,7 +601,7 @@ static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon,
*/
if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO ||
(opcode == FSCTL_QUERY_NETWORK_INTERFACE_INFO &&
- (tcon->ses->flags & CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES)))
+ test_bit(CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES, &tcon->ses->flags)))
return __smb2_plain_req_init(SMB2_IOCTL, tcon, server,
request_buf, total_len);
--
2.53.0
next reply other threads:[~2026-04-13 19:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-13 19:11 Henrique Carvalho [this message]
2026-04-13 19:11 ` [PATCH 2/2] smb: client: pass correct from_reconnect to cifs_put_tcp_session() Henrique Carvalho
2026-04-16 5:59 ` RAJASI MANDAL
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